Invasive micropapillary carcinoma of the breast: Eighty cases of an underrecognized entity

Eighty cases of infiltrating duct carcinoma of the breast with a pure or pa rtial micropapillary component are reported. The cases were analyzed using various parameters, including age at presentation, tumor size, tumor grade, presence of lymphatic invasion, and axillary lymph node status. The patien ts' age at presentation ranged from 36 to 92 years (mean, 58.8 years). Tumo r size ranged from 0.1 to 10 cm (mean, 2.0 cm); 67.5% (54 of 80) were poorl y differentiated, and 32.5% (26 of 80) were moderately differentiated; 62.5 % (50 of 80) of the cases had lymphatic invasion; 72.3% (47 of 65) of cases with axillary dissections had positive lymph nodes; and 25% (20 of 80) of the tumors were less than or equal to1.0 cm and 7.5% (6 of 80) were less th an or equal to0.5 cm. The characteristics of these small tumors with an inv asive micropapillary component have not previously been reported. Despite t heir minute size, these small micropapillary carcinomas seem to show the sa me proclivity for lymphatic spread and nodal dissemination as larger tumors with this unique histologic pattern. (C) 2001 by W.B. Saunders Company.